BIRMINGHAM, Alabama – One candidate, Paul DeMarco, has glided to the top of a crowded heap in the Alabama 6th Congressional District primary and made it into the two-man run-off and Gary Palmer is in second place after a number of lead changes for second-place candidates throughout the night.

Paul DeMarco, an Alabama state representative from Homewood, garnered 33 percent of the vote, and Alabama Policy Institute co-founder Gary Palmer had 20 percent of the vote -- a slight lead over the other three second place contenders: Gardendale state Sen. Scott Beason and Indian Springs surgeon Chad Mathis with 15 percent, and Harbert Management executive Will Brooke, who had 14 percent.

The battle for second place had different leaders throughout the night, with Beason, Mathis, Brooke and Palmer all sharing the runner-up spot, but Palmer pulled away later in the evening.

In Alabama's 6th, a heavily Republican seat being vacated at the end of this term by retiring U.S. Rep. Spencer Bachus, the winner of the Republican runoff could well decide the November general election. 99 percent of the district's 219 precincts are reporting.

"What a day, what a night," DeMarco said Tuesday night, addressing his supporters shortly after 10 p.m. at a campaign party at the W XYZ bar in the Aloft Hotel in Homewood. He thanked his supporters and volunteers, and his wife, Jacqueline.

Paul DeMarco and his wife, Jaqcueline DeMarco, at the W Hotel with supporters after making it into the Alabama 6th Congressional District Republican run-off on June 3, 2014. (Madison Underwood | AL.com)

"As I said, this has been a long journey, an incredible journey, but ladies and gentlemen we're only halfway there," DeMarco said. "And I will not take anything for granted. I have always run – and my team and volunteers have run – like they're behind. I don't know any other way."

DeMarco joked that he first had to get his wife's vote, and his wife said she wouldn't vote for him unless he got their newborn son to stop crying.

"Did I get it?" he asked Jacqueline, who stood on the podium next to him. "You're lucky I voted for you," she replied, laughing.

Palmer told AL.com he was "exhausted" after a long night, but confident he had made it into the run-off. He said the Mathis and Brooke campaigns had called to concede.

Asked how the race against DeMarco would proceed, Palmer told AL.com "it'll be a good issues-oriented discussion."

"I think the voters are going to have an opportunity to make a clear choice here. Paul's a good guy, and I think this will be a very civil and good race," Palmer said.

Asked how the campaign went, Palmer said he felt like he "did what I was supposed to do."

A matchup between Palmer and DeMarco could potentially trigger a national showdown between national tea party groups such as Club for Growth and business groups such as the U.S. Chamber of Commerce, according to conservative blogger and YellowhammerNews.com founder Cliff Sims.

Sims said he'd give DeMarco the edge due to his fundraising capability and the reputation he has in his district, but said there is, for Palmer, "an opportunity for a guy who has a lot of national connections to a lot of these tea party groups."

Leland Whaley, a conservative talk show host and the manager of Superstation 101 WYDE, told AL.com that Palmer is well-connected in fundraising circles due to his work with the Alabama Policy Institute, and could possibly challenge DeMarco on that front. Palmer could benefit from voter intensity problems, as well.

"I think voter intensity is a big issue because, as we get into the doldrums of summer and they have a low-turnout race and Palmer's able to have a pretty motivated base, that would be an advantage for him," Whaley said.